# PyPy[build-tool-web-frontend]

PyPy[build-tool-web-frontend]
news getting-started documentation svn issues contact EU/project

# Build tool web frontend

# What is it?

This document describes the web front-end for the 'build tool' that is part of the PyPy package, and used to compile PyPy on clients that participate in the PyPy build network. Both the build tool and this web front-end are generic, so they can be used for other projects too.

See the buildtool description for more details about the tool itself.

# Overview

The front-end consists of a single page, and uses XMLHttpRequest to communicate with the server. It presents a form that lets the user provide:

> - an email address

>   this to send mail to when a build is done, or has failed

> - system information

>   certain specifications of the system the build will run on, such as the operating system and cpu type

> - compilation options

>   the features the build should contain

> - svn revision/range

>   what svn revision to use, optionally with a range that specifies which other revisions are allowed

Once the user has filled in the form, the information is sent to the server where it is validated. If validation is not successful, a message is sent to the client about what fields need to be filled in, or clash (certain compilation options can clash); the user can modify the form and re-submit. If validation succeeds, a build is requested, which can either result in a URL returned (if a build is already available) or a message about whether a build is already in progress, or if the request is queued instead.

# Technical details

The form is a single static HTML page, that is blank when the user enters the page. The client then requests (using XMLHttpRequest) the form fields that are not static (system information + compilation options, email and svn info are hard-coded in the form), and presents them (using JavaScript that is generated from RPython using PyPy). The user can now fill in the form, when done it can press 'submit' to send the form contents to the server (again using XHR) for validation and (if validation is successful) execution. The results are sent back to the client and presented to the user: if it consists of validation error information it is presented in the form (as red fields or something), if it's a url it is presented as a download, and if it's a message it's alerted.

# Notes

Some random notes about implementation:

> - If this was a 'personal project', I would have used some simple templating language I wrote myself (Templess), but to not depend on some external lib, and to make it easier for others to work with this (or is it?) I decided to work with static HTML that is filled with JSON data from JS instead... Not sure if it indeed works out well, who knows at some point we may decide to use a templating language of some sort (you probably guess which I'd vote for ;) after all... Another option would be py.xml.html, although I don't like having to deal with presentation details from code too much...
> - The first idea I had for this application was to use pypy.translator.js.examples.web for the web server, which provides transparent XMLHttpRequest and JSON functionality... However, because this is rather ad-hoc, and doesn't seem suitable for production situations, I decided that was not a good idea... Making it more suitable for production doesn't seem like an easy task (currently it uses BaseHTTPServer for instance), although very tempting, since this can imo become one of the most interesting web application frameworks available... If this would be made solid and more usable (read: more docs and a cleaner, higher level API), especially after adding features like transparent session handling, better HTTP support and more browser abstractions, it can make development of larger web applications that use 'AJAX' (XMLHttpRequest, perhaps with some XML) a lot easier, I think...